I am having the nvidia black screen issue. I tried rolling back the drivers back to 384.90 and even tried manually installing the nvidia 384.111 drivers from the nvidia website using NVIDIA-Linux-x86_64-384.111.run.
It appears that every nvidia driver higher than 384 will cause this problem. In order to get it working again it appears that the kernel cannot be updated past 4.13. In addition to this the nvidia proprietary drivers can’t be upgraded past 384.90 which are the highest 384 versioned drivers available from the arch archives. With Runescape Wiki ignoring this issue on the forums there's not much else that can be done.
Here's a list of URLS to the arch archive.
DKMS for those who prefer that instead:
For the adventurous: http://us.download.nvidia.com/XFree86/Linux-x86_64/384.111/NVIDIA-Linux-x86_64-384.111.run
This apparently works on 4.14 according to some information I found on the runescape official forums. But I didnt try it.
Hope this is fixed soon.
I downgraded my kernel to 4.13.7-1, installed the related kernel headers, and then downgraded the nvidia drivers to nvidia-dkms-384.90-1. That fixed my issue completely. There's definitely something wrong with the NXT client.